1. Field of the Invention
The present invention relates to a cleaning system that utilizes a cleaning fluid to remove grease and other foreign debris such as flux from an object.
2. Description of Related Art
It is sometimes desirable to remove grease, oils, flux and other foreign debris from an object. For example, electronic circuit boards are typically de-greased before insertion into a solder machine. The de-greasing process insures better adhesion of the solder to the board, thereby improving the life of the solder joint.
Cleaning and de-greasing operations are typically performed in a closed tank. The tank usually contains a vaporized cleaning agent such as a chlorofluorocarbon, trichloroethylene or methyl chloride. The use of conventional de-greasing tanks typically results in the release of solvent vapors into the atmosphere. It is now known that conventional de-greasing chemicals such as chlorofluorocarbons, deplete the ozone and produce other negative environmental side effects.
U.S. Pat. No. 5,106,404 issued to Grant discloses a cleaning system that evacuates the solvent from the cleaning chamber before the lid and part are removed from the tank. Although effective in reducing the release of solvents, the solvents can still escape through the interface between the lid and the tank. It would therefore be desirable to have a seal system between the lid and tank to insure that the vaporized cleaning agent does not escape the cleaning chamber and contaminate the environment.
Conventional cleaning systems typically maintain the cleaning solvent in a vaporized state. The Grant patent discloses a cleaning system which cycles the pressure of the cleaning chamber so that the solvent goes through a number of vaporizing and condensing cycles. Such a process has been found to remove contaminants embedded in the part. The pressure cycling process disclosed in Grant requires additional logic circuitry and increases the cycle time needed to clean the part. It would be desirable to provide a cleaning system and process that increases the aggressiveness of the cleaning fluid without cycling the system. It would also be desirable to provide a system that can use an aggressive non-toxic cleaning fluid.